The present invention relates generally to television receivers. More specifically, the present invention relates to a method and apparatus for adaptively comb filtering a television signal so that the chrominance and luminance components may be decoded without unwanted artifacts.
"Artifacts", as used in the body of the present letters patent refers to disturbances appearing on the display device of a television receiver resulting from the separation of the chrominance and luminance components of a received composite video signal, usually in the form of so called cross-luminance or cross-chrominance effects (also known as hanging dots and crawling dots).
Prior art comb filter circuits, while improving on the resolution of the decoded television signals, as compared to older methods using only horizontal filtering techniques, produce the above-mentioned artifacts during the separation process. These artifacts are exacerbated in the display of receivers employing prior art comb filters--especially during the occurrence of vertical and horizontal edges. Edges may be defined as regions of sharp transitions in either luminance or chrominance.